from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt
from passlib.context import CryptContext
from app.core.config import settings
from app.schemas.user import TokenData
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from app.models.user import UserType

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="auth/admin")

def verify_password(plain_password: str, hashed_password: str) -> bool:
    return pwd_context.verify(plain_password, hashed_password)

def get_password_hash(password: str) -> str:
    return pwd_context.hash(password)

def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
    return encoded_jwt

async def get_current_user(token: str = Depends(oauth2_scheme)) -> TokenData:
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        user_type = UserType(payload.get("user_type"))
        permission_level = int(payload.get("permission_level", 0))
        token_data = TokenData(
            username=username,
            user_type=user_type,
            permission_level=permission_level
        )
    except JWTError:
        raise credentials_exception
    return token_data

def check_admin_permission(token_data: TokenData = Depends(get_current_user)):
    if token_data.user_type != UserType.ADMIN:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Not enough permissions"
        )
    return token_data 